This invention relates generally to an electromagnetic, clutch-brake, positioning assembly for use in applications which require precise, positional control, and in particular, it relates to such an assembly which is able to adjust automatically for wear in a brake pad associated with the assembly to thereby maintain such precise positional control.
One of the problems with prior-art, clutch-brake assemblies is that they do not maintain precise positional control when used extensively over a period of time. For example, a "wrap-spring clutch" may be used typically in an endorser which, in turn, is used in financial systems. One of the functions which an endorser performs is to print the name of the bank or financial institution which processes the documents on the back of each document, like a check which is processed by the bank. In the endorsing process mentioned, the wrap-spring clutch is used to position the printing drum of a drum-type endorser to "roll" the information on the back of a document in the correct position on the document moving along a document track associated with the endorser. This rolling-on of information occurs in less than one complete revolution of the printing drum, and before the revolution is completed, the printing drum has to be stopped in the correct location so as to position it for the next document being moved in the document track. When the wrap-spring clutch mentioned is used for a period of time, it loses its positional control.